﻿#define _CRT_SECURE_NO_WARNINGS 1
#include"Stack.h"

//初始化栈
void STInit(ST* ps)
{
	assert(ps);

	ps->arr = NULL;
	ps->capacity = ps->top = 0;
}

// 销毁栈
void STDestroy(ST* ps)
{
	assert(ps);

	if (ps->arr)
		free(ps->arr);
	ps->arr = NULL;
	ps->capacity = ps->top = 0;
}

// ⼊栈
void STPush(ST* ps, STDataType x)
{
	assert(ps);

	//判断空间是否足够
	if (ps->capacity == ps->top)
	{
		int newcapacity = ps->capacity == 0 ? 4 : 2 * ps->capacity;
		STDataType* tmp = (STDataType*)realloc(ps->arr, newcapacity * sizeof(STDataType));
		if (tmp == NULL)
		{
			perror("realloc fail!");
			exit(1);
		}
		ps->arr = tmp;
		ps->capacity = newcapacity;
	}
	//空间足够
	ps->arr[ps->top++] = x;
}
//出栈
void STPop(ST* ps)
{
	assert(ps);
	assert(!STEmpty(ps));

	--ps->top;
}
//取栈顶元素
STDataType STTop(ST* ps)
{
	assert(ps);
	return ps->arr[ps->top-1];
}
//获取栈中有效元素个数
int STSize(ST* ps)
{
	assert(ps);
	return ps->top;
}
//栈是否为空
bool STEmpty(ST* ps)
{
	assert(ps);
	return ps->top == 0;
}